Method and apparatus for sterilizing preform

ABSTRACT

A preform is easily and speedily sterilized. A number of preforms, each having a bottomed tubular shape, are laid on a conveyer in a scraggly overturned manner, these preforms passes inside a chamber together with the conveyer, and hydrogen peroxide water mist is sprayed from both sides of the conveyer in a direction crossing the conveyer in the chamber, thereby adhering the sprayed hydrogen peroxide water to inner and outer surfaces of the preforms on the conveyer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/384,697, filed Sep. 12, 2014, which in turn is the National Stageentry of International Application No. PCT/JP2013/057016, filed Mar. 13,2013, which designated the United States, the entireties of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for sterilizinga preform for manufacturing a container such as bottle.

BACKGROUND OF THE INVENTION

In a conventional technology, in order to sterilize a bottle made of PET(polyethylene terephthalate) with hydrogen peroxide water, the bottle isguided into a chamber, the hydrogen peroxide water is sprayed within thechamber, and air is guided into the chamber to pass therethrough.According to such operation, even if the bottle has a complicated shape,mist of the hydrogen peroxide water uniformly adheres to a surface ofthe bottle to thereby uniformly sterilize the bottle surface (forexample, refer to Patent Document 1).

Furthermore, it has been attempted to sterilize a preform in a preformstage before forming a bottle. That is, in a state in which a mouthportion of the preform is directed to a nozzle that is opened at avertically downward of the preform mouth portion, a chemical agent suchas hydrogen peroxide is jetted from the nozzle, the preform isthereafter guided into a heating furnace to thereby heat the preform toa temperature suitable for a blow molding process and enhancesterilizing effect, and thereafter, the preform is clamped by a formingmold and blow-molded into a bottle (for example, refer to PatentDocument 2).

Furthermore, when the preform is sterilized in a preform stage, it hasbeen attempted to put a number of preforms into which hydrogen peroxidewater has been dropped respectively into a container, which is thensealed, and to sterilize inner and outer surfaces of these preforms withsteam of the hydrogen peroxide water that is evaporated in the containerat a time of transporting and maintaining the container. The preformstaken out from the container at a container receiving station is moldedthere into bottles in an aseptic state by a molding machine (forexample, refer to Patent Document 3)

Still furthermore, there may be a case in which a use of sterilizingagent such as hydrogen peroxide or like is not desirable forsterilization of a preform. In such a case, as a method for sterilizingthe preform with no use of the sterilizing agent, there has beenprovided a method in which water steam is blasted into to heat a preformto a temperature more than glass-transition point and maintain thattemperature for a predetermined time for sterilizing the interior of thepreform, and immediately thereafter, air is blasted into the preform toremove steam drain from the preform (for example, refer to PatentDocument 4).

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese Patent Laid-open Publication No. HEI 5-65148

Patent Document 2: Japanese Translation of PCT international ApplicationPublication No. 2001-510104

Patent Document 3: Japanese Patent Laid-open Publication No. 2000-326935

Patent Document 4: Japanese Patent Laid-open Publication No. 2007-111886

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

It is required for a conventional method for sterilizing a bottle usinghydrogen peroxide mist to miniaturize the hydrogen peroxide mist, whichrequires use of expensive mist generator, leading to cost up, thus beinginconvenient.

Further, it is required for a method for jetting a chemical agent suchas hydrogen peroxide or like to a preform to travel the preforms in avertically elected and aligned state, and moreover, it is required toimmediately guide the preforms after the adhesion of the chemical agentinto a heating furnace. Because of this reason, a sterilization systemis made complicated and is increased in size, leading to cost up formanufacture.

Furthermore, for a method for sterilizing a preform by dropping hydrogenperoxide solution into the preform, it is required to convey thepreforms in an aligned state, and accordingly, it is difficult to dealwith a number of preforms at a high speed. Moreover, since it isnecessary to drop the hydrogen peroxide solution into each preform witha predetermined quantity, an expensive device for discharging thehydrogen peroxide solution while measuring the predetermined quantity isneeded, thus being defective and disadvantageous.

Still furthermore, according to the conventional method in which theinterior of the preform is sterilized using steam, a problem such that asterilizing agent may remain is solved. However, if drain of the steamremains inside the preform, such remaining steam drain may cause areason for generation of whitening at a time of molding the preform intoa container, and hence, it is required to provide a process for removingthe drain after the sterilization, thus providing a problem. Inaddition, when the steam is applied to the mouth portion of the preformfor a long time, the mouth portion is liable to be deformed, which maycause a loss of sealing performance when a lid is applied to the mouthportion. Moreover, the sterilization only by the steam may cause aproblem such that bacteria or like easily remains alive.

An object of the present invention is to solve the problem and/orinconvenience mentioned above.

Means for Solving the Problem

To achieve the above object, the present invention adopts the followingconfigurations.

That is, the invention according to a first aspect adopts a method forsterilizing a preform, wherein a number of preforms (1), each having abottomed tubular shape, are loaded on a conveyer (4) in a scragglyoverturned manner, the preforms (1) pass through a chamber (5) togetherwith the conveyer (4), and hydrogen peroxide water is sprayed within thechamber (5) from both sides of the conveyer (4) in a direction crossingthe conveyer (4), thereby adhering the hydrogen peroxide water to innerand outer surfaces of each of the preforms (1) on the conveyer (4).

There is provided a method for sterilizing a preform wherein a number ofpreforms, each having a bottomed tubular shape, are loaded on a conveyerin a scraggly overturned manner, the preforms pass through a chambertogether with the conveyer, hydrogen peroxide water is sprayed withinthe chamber from both sides of the conveyer in a direction crossing theconveyer to thereby adhere the hydrogen peroxide water to inner andouter surfaces of each of the preforms on the conveyer, and thereafter,superheated steam having a temperature of 200° C. to 500° C. made fromwater is blasted to at least the inner surface of all surfaces of thepreform including a mouth portion thereof at a pressure more thanatmospheric pressure.

As recited in a second aspect or a third aspect of the presentinvention, in the preform sterilizing method according to the firstaspect of the present invention, it may be preferred that in the whereinthe hydrogen peroxide water is atomized into mist by a two-fluid sprayusing pressurized air.

As recited in a fourth aspect of the present invention, in the preformsterilizing method according to any one of the first to third aspects ofthe present invention, it may be preferred that concentration of thehydrogen peroxide water is within 20% to 35%.

As recited in a fifth aspect of the present invention, in the preformsterilizing method according to any one of the third or fourth aspectsof the present invention, it may be preferred that hot air having atemperature of 40° C. to 150° C. is mixed with the mist of the hydrogenperoxide water.

As recited in a sixth aspect of the present invention, in the preformsterilizing method according to any one of the first to fifth aspects ofthe present invention, it may be preferred that an interior of thechamber (5) is preliminarily sterilized by spraying the hydrogenperoxide water before starting the sterilization of the preform (1).

The invention according to a seventh aspect adopts an apparatus forsterilizing a preform comprising: a conveyer (4) on which a preform (1),having a bottomed tubular shape, is laid in an overturned manner; achamber (5) provided to a horizontally traveling portion of the conveyer(4); and a spray nozzle (10) that sprays hydrogen peroxide water fromboth sides of the conveyer (4) in a direction crossing the conveyer (4)in the chamber so as to adhere the hydrogen peroxide water to inner andouter surfaces of the preform (1) on the conveyer (4).

The invention according to an eighth aspect adopts an apparatus forsterilizing a preform comprising: a conveyer (4) on which a preform (1),having a bottomed tubular shape, is laid in an overturned manner; achamber (5) provided to a horizontally traveling portion of the conveyer(4); a spray nozzle (10) that sprays hydrogen peroxide water (M) fromboth sides of the conveyer (4) in a direction crossing the conveyer (4)in the chamber (5) so as to adhere the hydrogen peroxide water to innerand outer surfaces of the preform (1) on the conveyer (4); and asuperheated steam supplying means that blasts superheated steam (S)having a temperature of 200° C. to 500° C. made from water is blasted toat least the inner surface of all surfaces of the preform (1) includinga mouth portion (1 a) thereof at a pressure more than atmosphericpressure while receiving the preform (1) discharged outside of thechamber (5) from the conveyer (4) and travelling the preform (1) in anelected posture.

The invention according to a ninth aspect adopts a method forsterilizing a preform wherein a number of preforms (1), each having abottomed tubular shape, are loaded on a conveyer (4) in a scragglyoverturned manner, the preforms (1) pass through a first chamber (5) bythe conveyer (4), hot air (H) is sprayed during passing inside the firstchamber (5) from both sides of the conveyer (4) in a direction crossingthe conveyer (4) to thereby preheat the preform (1), and superheatedsteam (S) made from water is blasted toward the preform (1) from bothsides of the conveyer (4), while passing the preforms (1) in a secondchamber (6) to thereby sterilize the preforms (1).

As recited in a tenth aspect of the present invention, in the preformsterilizing method according to the ninth aspect of the presentinvention, it may be preferred that the preform (1) is preheated to atemperature of 40° C. to 70° C. by blasting the hot air (H).

As recited in an eleventh aspect of the present invention, in thepreform sterilizing method according to the ninth aspect of the presentinvention, it may be preferred that the superheated steam (S) isproduced by induction heating water mixed with the hydrogen peroxide.

The invention according to a twelfth aspect adopts an apparatus forsterilizing a preform comprising: a conveyer (4) on which a preform (1),having a bottomed tubular shape, is laid in an overturned manner; firstand second chambers (5, 6) provided in series to a horizontallytravelling portion of the conveyer (4); a preheating nozzle (11) thatblasts hot air (H) from both sides of the conveyer (4) toward thepreforms in the first chamber (5); and a sterilizing nozzle (20) thatblasts superheated steam (S) made from water mixed with hydrogenperoxide from both sides of the conveyer (4) toward the preforms in thesecond chamber (6) to thereby sterilize the preforms (1).

The invention according to a thirteenth aspect adopts a method forsterilizing a preform wherein a number of preforms (1), each having abottomed tubular shape, are loaded on a conveyer (4) in a scragglyoverturned manner, the preforms (1) pass through a first chamber (5) bythe conveyer (4), hot air (H) is blasted during passing inside the firstchamber (5) from both sides of the conveyer (4) in a direction crossingthe conveyer (4) to thereby preheat the preform (1), and superheatedsteam (S) is thereafter blasted toward the preforms (1) from both sidesof the conveyer (4), while the preforms (1) passing in a second chamber(6) to thereby sterilize the preforms (1).

As recited in a fourteenth aspect of the present invention, in thepreform sterilizing method according to the thirteenth aspect of thepresent invention, it may be preferred that the preform (1) is preheatedto a temperature of 40° C. to 70° C. by blasting the hot air (H).

As recited in a fifteenth aspect of the present invention, in thepreform sterilizing method according to the thirteenth aspect of thepresent invention, it may be preferred that the superheated steam (S) isproduced by induction heating water mixed with the hydrogen peroxide.

The invention according to a sixteenth aspect adopts an apparatus forsterilizing a preform comprising: a conveyer (4) on which a preform (1),having a bottomed tubular shape, is laid in an overturned manner; firstand second chambers (5, 6) provided in series to a horizontallytravelling portion of the conveyer (4); a preheating nozzle (11) thatblasts hot air (H) from both sides of the conveyer (4) toward thepreforms (1) in the first chamber (5); and a sterilizing nozzle (20)that blasts superheated steam (S) from both sides of the conveyer (4)toward the preforms (1) in the second chamber (6) to thereby sterilizethe preforms (1).

Effects of the Invention

According to the invention of the first aspect, there is provided amethod of sterilizing a preform wherein a number of preforms (1), eachhaving a bottomed tubular shape, are loaded on a conveyer (4) in ascraggly overturned manner, the preforms (1) pass through a chamber (5)together with the conveyer (4), and hydrogen peroxide water is sprayedwithin the chamber (5) from both sides of the conveyer (4) in adirection crossing the conveyer (4), thereby adhering the hydrogenperoxide water to inner and outer surfaces of each of the preforms (1)on the conveyer (4). Accordingly, the preform (1) discharged from thepreform molding machine is received by the conveyer (4) and the preformis then guided into the chamber (5) together with the conveyer (4) onwhich the preform (1) 1 is laid in the overturned state. Within thechamber (5), the hydrogen peroxide water is sprayed from both sides ofthe conveyer (4) in the direction crossing the conveyer, so that themist of the hydrogen peroxide water adheres on the outer surface of thepreform (1) on the conveyer (4). At this time, since the preform isoverturned on the conveyer (4) by the vibration or like, the hydrogenperoxide water can uniformly adhere to the outer surface of the preform.Furthermore, the mist of the hydrogen peroxide water flows into theoverturned preform through the mouth portion (1 a) thereof to therebyalso uniformly adhere to the inner surface of the preform (1). Thus, theentire surface of the preform (1) can be suitably sterilized by thehydrogen peroxide. In addition, as a result of adoption of the aboveinvention, it is not necessary to use conventionally used preformaligning device and expensive hydrogen peroxide generator fordischarging constant amount of the hydrogen peroxide water, and hence, alot of preforms can be easily sterilized with reduced cost.

According to the invention of the second aspect, there is provided amethod for sterilizing a preform wherein a number of preforms (1), eachhaving a bottomed tubular shape, are loaded on a conveyer (4) in ascraggly overturned manner, the preforms (1) pass through a chamber (5)together with the conveyer (4), hydrogen peroxide water is sprayedwithin the chamber (5) from both sides of the conveyer (4) in adirection crossing the conveyer (4) to thereby adhere the hydrogenperoxide water to inner and outer surfaces of each of the preforms (1)on the conveyer (4), and thereafter, superheated steam (S) having atemperature of 200° C. to 500° C. made from water is blasted to at leastthe inner surface of all surfaces of the preform (1) including a mouthportion (1 a) thereof at a pressure more than atmospheric pressure.Accordingly, the preform (1) discharged from the preform molding machineis received by the conveyer (4) and the preform is then guided into thechamber (5) together with the conveyer (4) on which the preform (1) 1 islaid in the overturned state. Within the chamber (5), the hydrogenperoxide water is sprayed from both sides of the conveyer (4) in thedirection crossing the conveyer, so that the mist (M) of the hydrogenperoxide water adheres on the outer surface of the preform (1) on theconveyer (4). At this time, since the preform is overturned on theconveyer (4) by the vibration or like, the hydrogen peroxide water canuniformly adhere to the outer surface of the preform. Furthermore, themist (M) of the hydrogen peroxide water flows into the overturnedpreform through the mouth portion (1 a) thereof to thereby alsouniformly adhere to the inner surface of the preform (1). Thus, theentire surface of the preform (1) can be suitably sterilized by thehydrogen peroxide. In a certain case in which the preforms (1) thussterilized by the hydrogen peroxide is packaged and stored, and thepackage is thereafter delivered and opened, and then sent to theblow-molding machine or like, the superheated steam (S) is blasted atthe time of being supplied to the blow-molding machine, so that thesterilization can be more surely performed, and thereafter is moldedinto a container by the blow-molding machine. In the meantime, in a casewhere the preform sterilized by the hydrogen peroxide is supplied as itis to the blow-molding machine or like, the preform is sterilized by thesuperheated steam (S) in a process of being transferred from theconveyer (4) to the blow-molding machine, so that the surely sterilizedpreform (1) is molded into a container (12) by the flow-molding machine.

In addition, as a result of adopting the above method of the presentinvention, it is not necessary to use conventionally used preformaligning device and expensive hydrogen peroxide generator fordischarging constant amount of the hydrogen peroxide water, and hence, alot of preforms can be easily sterilized with reduced cost.

According to the invention of the ninth aspect, the preform (1)discharged from the preform molding machine is received by the conveyer(4) and the preform is then guided into the first and second chambers(5, 6) together with the conveyer (4) on which the preform (1) 1 is laidin the overturned state. Within the second chamber (6), the superheatedsteam (S) is blasted from both sides of the conveyer (4), so that theouter surface of the preform (1) on the conveyer (4) can be suitablysterilized. In addition, at this time, since the preform is overturnedon the conveyer (4) by the vibration or like, the superheated steam (S)can uniformly adhere to the outer surface of the preform. Furthermore,the superheated steam (S) flows into the overturned preform (1) throughthe mouth portion (1 a) thereof to thereby also uniformly adhere to theinner surface of the preform (1). Thus, the entire surface of thepreform (1) can be uniformly sterilized by the superheated steam (S).

Furthermore, since the superheated steam (S) is made from water mixedwith the hydrogen peroxide, spore-forming bacteria can be alsosterilized as well as general bacteria, fungus, yeast or like adheringto the surface of the preform (1).

Moreover, beforehand the sterilization by the blasting of thesuperheated steam (S), since the preform (1) is preheated in the firstchamber (5) by blasting the hot air (H), even if using amount of thesuperheated steam (S) is reduced, desired sterilizing effect isattainable.

According to the invention of the thirteenth aspect, the preform (1)discharged from the preform molding machine is received by the conveyer(4) and the preform is then guided into the first and second chambers(5, 6) together with the conveyer (4) on which the preform (1) is laidin the overturned state. Within the second chamber (6), the superheatedsteam (S) is blasted from both sides of the conveyer (4), so that theouter surface of the preform (1) on the conveyer (4) can be suitablysterilized. In addition, at this time, since the preform is overturnedon the conveyer (4) by the vibration or like, the superheated steam (S)can uniformly adhere to the outer surface of the preform. Furthermore,the superheated steam (S) flows into the overturned preform (1) throughthe mouth portion (1 a) thereof to thereby also uniformly adhere to theinner surface of the preform (1). Thus, the entire surface of thepreform (1) can be uniformly sterilized by the superheated steam (S).

Moreover, beforehand the sterilization by the blasting of thesuperheated steam (S), since the preform (1) is preheated in the firstchamber (5) by blasting the hot air (H), even if using amount of thesuperheated steam (S) is reduced, desired sterilizing effect isattainable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(A) and 1(B) represent one example of a preform capable of beingsterilized by a sterilization method according to the present invention,in which FIG. 1(A) is a plan view and FIG. 1(B) is a front view.

FIG. 2 is a partially cut-off plan view schematically showing anapparatus for carrying out a method of sterilizing a preform withhydrogen peroxide.

FIG. 3 is a vertical sectional view showing a schematic structure of theapparatus mentioned above.

FIG. 4 is an explanation view showing a method of sterilizing thepreform with superheated steam.

FIGS. 5(A)-5(C) are explanation views explaining processes from aprocess of sterilizing the preform with superheated steam to a processof blow-molding the preform.

FIGS. 6(D)-6(F) are explanatory views showing processes to a cappingprocess after the blow-molding process.

FIG. 7 is a schematic plan view showing a machine for filling thepreform with drink after the sterilization with the hydrogen peroxide,the sterilization with superheated steam and the blow molding.

FIG. 8 is a partially cut-off plan view showing a schematic structure ofan apparatus for carrying out a method of sterilizing a preformaccording to the present invention.

FIG. 9 is a vertical sectional view showing a schematic structure of theapparatus mentioned above.

FIG. 10(A) is a block diagram of a hot air generating portion, and FIG.10(B) is a block diagram of a superheated steam generating portion.

DETAILED DESCRIPTION OF THE INVENTION

Hereunder, embodiments for carrying out present invention will bedescribed.

Embodiment 1

A preform as an object to be sterilized by the present invention isformed by injection molding a PET into a test-tube like bottomed tubularmember. The preform is thereafter formed into a bottle having a desiredshape (see FIG. 6(D)), and as shown in FIGS. 1(A) and 1(B), a preform 1is formed with a mouth portion 1 a having a shape similar to that of abottle after the molding at an initial time for the molding. A malescrew portion 2 is formed on an outer peripheral surface of the mouthportion 1 a at the same time as the time of molding the preform 1. Themale screw portion 2 is engageable with a female screw portion of a cap,not shown, to be applied to the mouth portion 1 a of the bottle. Belowthe male screw portion 2, a support ring 3 utilized at a time of fillingdrink in a bottle is formed.

An apparatus for sterilizing such preform 1 has a structure representedby FIGS. 2 and 3.

In FIGS. 2 and 3, reference numeral 4 denotes a belt-type conveyer. Apreform molding machine, not shown, is arranged on an upstream side inthe travelling direction shown with arrow of the conveyer 4. The moldedpreform 1 released from the preform molding machine is received by ahopper or like, not shown, on an upstream side of the conveyer 4. Asshown in FIG. 2, the molded preforms 1 are laid on the conveyer in ascraggly overturned posture.

A middle section of the conveyer 4 can be traveled in the horizontaldirection, and a chamber member 5 is applied in form of hood to thismiddle section of the conveyer 4.

The chamber member 5 is composed of both side wall sections 6 disposedso as to sandwich the conveyer 4 from both sides, front and rear wallsections 7, 8 disposed at front and rear end portions of the side wallsections 6, and a top wall section 9 disposed so as to shield the uppersides of the both side wall sections 6 and the front and rear wallsections 7, 8. The chamber member 5 may be called merely chamber 5hereinafter.

Spray nozzles 10, that spray the hydrogen peroxide water in a directioncrossing the conveyer 4 from the side edge sides thereof, are mounted toboth the side wall sections 6, respectively. Although the spray nozzles10 may be mounted one by one to both the side wall sections 6, it ispreferred to arrange plural number of the spray nozzles 10 are arrangedto both the side wall sections 6 along the travelling direction of theconveyer 4.

Moreover, as the spray nozzles 10, it is desirable to adopt two-fluidnozzles, in which the hydrogen peroxide water is supplied from one fluidpath of the respective nozzles 10 and pressurized air is also suppliedfrom the other one fluid path thereof.

When the pressurized air flows within the two-fluid spray nozzle 10 athigh speed, the hydrogen peroxide water is taken up by the pressurizedair to thereby form hydrogen peroxide mist, which is then dischargedinto the chamber 5 from the tip end of each spray nozzle 10. Thishydrogen peroxide mist is sprayed and adheres to the surface of thepreform 1 now travelling on the conveyer 4.

It may be possible to spray mixture of such hydrogen peroxide mist andhot air (heated air) having temperature of 40 to 150° C. to the preform1.

With reference to FIGS. 2 and 3, reference numeral 46 demotes a nozzlethat jets such hot air. The hot air jetted from this nozzle 46 is mixedwith the mist of the hydrogen peroxide water generated by the two-fluidspray nozzle 10 and the mixture then flows toward the preform 1 whileheating the mist. By heating the mist, the sterilizing effect can beenhanced.

The mist of the hydrogen peroxide water is discharged in the directioncrossing the conveyer 4 from both sides of the conveyer 4 within thechamber 5, and the preform 1 is overturned on the conveyer 4 byvibration or like, so that the hydrogen peroxide water can uniformlyadheres to the outer surface of the preform. At the same time, thehydrogen peroxide mist flows into the horizontally overturned preform 1through the mouth portion 1 a thereof to thereby also uniformly adhereto the inner surface of the preform 1. Furthermore, since the hydrogenperoxide mist discharged from the two-fluid spray nozzle 10 fills theinterior of the chamber 5 and circulates therein, the circulated mistalso uniformly adheres to the surface of the preform 1. According tothis manner, the entire surface of the preform 1 can be suitablysterilized by the hydrogen peroxide.

It is preferred for the hydrogen peroxide used for the sterilization ofthe preform 1 to have concentration of 20 to 35%. In the case of theconcentration being less than 20%, there may cause a case wherespore-forming bacteria remains alive which may lead to defectivesterilization, and on the other hand, in the case of the concentrationbeing more than 35%, much amount of the hydrogen peroxide may remain onthe preform.

Further, it is preferred that the hot air of temperature of 40 to 150°C. is mixed with the mist. In the case of the temperature being lessthan 40° C., the sterilization may become defective, and on the otherhand, in the case of the temperature being more than 150° C., therelikely causes a case of the preform being deformed.

The front and rear wall sections 7 and 8 of the chamber 5 are formedwith openings 7 a and 8 a through which the conveyer 4, on which thepreform 1 is placed, can pass. The top wall section 9 is connected to anexhaust duct 11. The mist of the hydrogen peroxide discharged into thechamber 5 is sucked into the exhaust duct by driving a blower, notshown, and then flows toward a recovery device. According to theoperation mentioned above, the hydrogen peroxide mist is prevented fromflowing out of the chamber 5 through the openings 7 a and 8 a formed tothe front and rear wall sections 7 and 8 and the like.

The downstream side of the conveyer 4 than the chamber 5 extends towarda large-sized container or like, not shown. The preform 1 to which thehydrogen peroxide mist adheres within the chamber 5 is conveyed towardand into the large-sized container. The container is closed and sealedafter predetermined numbers of the preforms 1 are loaded, stored andthen transferred to a factory at which the preform 1 is molded into abottle. During such storing and transferring of the preforms 1, thepreforms 1 are sterilized by the hydrogen peroxide which is also trappedin the container.

Further, in an arrangement in which the downstream side of the conveyer4 than the chamber 5 is connected to a blow-molding machine, thesterilized preform 1 is directly subjected to the blow-molding treatmentso as to form a container such as bottle. Moreover, in an arrangement inwhich the blow-molding machine is connected to a content fillingmachine, the content such as drink fills the container such as bottle,the bottle is sealed and then discharged as aseptic packaged product inwhich the content fills.

Hereunder, function of the preform sterilization apparatus mentionedabove will be explained together with a preform sterilization method.

Beforehand the starting of the sterilization treatment of the preform 1,the hydrogen peroxide water is preliminarily sprayed into the chamber 5from the spray nozzle 10 to thereby sterilize the interior of thechamber 5.

By driving the preform molding machine, the molded preforms 1 are put onthe upstream side of the travelling conveyer 4. The preforms 1 releasedfrom the preform molding machine are received on the upstream sideportion of the conveyer 4, and as shown in FIG. 2, the preforms are laidon the conveyer 4 in a scraggly appearance.

The preforms 1 on the conveyer 4 enter the chamber 5 together with theconveyer 4 and are sprayed with the hydrogen peroxide water through thespray nozzle 10.

The hot air to be jetted from the nozzle 46 is mixed, as occasiondemands, with the sprayed mist of the hydrogen peroxide water.

The hydrogen peroxide mist is discharged from both the sides of theconveyer in the direction crossing the conveyer 4 within the chamber 5.Further, since the preform 1 is overturned on the conveyer by vibrationor like, the hydrogen peroxide water can uniformly adheres to the outersurface of the preform 1.

The hydrogen peroxide mist flows into the interior of the horizontallylaying preform 1 through the mouth portion 1 a of the preform 1 tothereby uniformly adhere to the inner surface thereof.

Further, since the hydrogen peroxide mist discharged through the spraynozzle 10 fills the chamber 5 and circulates therein, the mist alsouniformly adheres, while flowing, to the surface of the preform 1, thusthe entire surface of the preform 1 being uniformly sterilized by thehydrogen peroxide.

The preform 1 passes through the chamber 5 together with the conveyer 4while being blasted with the hydrogen peroxide mist and is put into thelarge-sized container or like, and otherwise, the preform 1 is conveyedto the blow-molding machine and the filling machine without being loadedinto the large-sized container, and is then discharged as an asepticpackaged product.

It is further to be noted that the present invention is not limited tothe described embodiment, and other various embodiments or modes may beadopted as examples for embodiment.

Example 1

Mist of hydrogen peroxide water was produced by supplying hydrogenperoxide water of 35% concentration and pressurized air to a two-fluidspray, the thus produced mist was mixed with hot air having temperatureof 60° C., and then, the mist of the hydrogen peroxide water was sprayedinside a chamber through a nozzle. The chamber is a box-shaped member,having no bottom, having a size of 1,000 mm width, 1,500 mm length and200 mm height, and the box-shaped chamber was set to a predeterminedposition on the conveyer having 600 mm width. Preforms of the number of860 bottles/min., each being formed into a bottle of 500 mm, weresupplied to the conveyer, which is driven at a speed of 0.2/sec. At thistime, the hydrogen peroxide water of amount of about 50 mg adhered toeach preform.

The sterilizing power was evaluated with the BaciLLus subtiLis beingindicator fungus, 4.2 D and 5.3 D were obtained with respect to theinner surface of the preform and the outer surface thereof,respectively.

Further, when such preform as mentioned above was molded into a bottleand water filled the bottle, remaining amount of the hydrogen peroxidewas measured. The remaining amount thereof was 0.012 ppm.

Embodiment 2

Hereunder, an embodiment 2 of the present invention will be described.

A preform as an object of the present invention to which sterilizationis performed is the same as that of the first embodiment 1 describedhereinbefore.

Furthermore, an apparatus for sterilizing the preform 1 has the samestructure as that of the first embodiment 1. The preform 1 to which themist M of the hydrogen peroxide water adheres within the camber 5 isconveyed to and loaded into a large-sized container by the conveyer 4.The large-sized container into which the preforms of the predeterminednumbers are accommodated is thereafter sealed, stored therein and thentransferred to a factory at which the preform is molded into a bottle.During such storing and transferring of the preforms 1, the preforms 1are sterilized by the hydrogen peroxide which is also trapped in thecontainer.

The large-sized container is transferred to another factory at whichpackage is opened, and the preforms 1 taken out therefrom are subjectedto treatment described hereinafter, and then, formed into a productpackage in an aseptic state (see FIG. 6(F)).

As shown in FIG. 4, the further sterilization of the preform 1 that hasbeen already sterilized by the hydrogen peroxide is performed byblasting superheated steam S, having temperature of 200 to 500° C. andsubstantially atmospheric pressure, generated from water to the entireinner and outer surfaces of the preform 1 including the mouth portion 1a thereof.

It is preferred that the superheated steam to be blasted to the preformhas a temperature of 200 to 500° C., and more preferably, 250 to 400° C.In the case of the temperature range within 200 to 500° C., only thesurface of the preform is exposed to high heat temperature to therebyspore-forming bacteria adhering to the surface of the preform can besterilized for a short time. In a case of less than 200° C., it isrequired for the preform to be blasted with the superheated steam for along time for the sufficient sterilization, which leads to highlyincreased temperature to a PET forming the preform, and the preform isliable to be deformed. On the other hand, in a case of more than 500°C., the PET forming the preform is itself highly heated for a shorttime, which also leads to ready deformation of the preform.

The pressure of the superheated steam to be blasted to the preform is apressure higher than atmospheric pressure, preferably of higher than 0.1MPa and less than 0.3 MPa. In a case of near 0.1 MPa, even if thetemperature is lowered in contact of the superheated steam to thepreform, there is less possibility of condensation of the steam, but inthe case of more than 0.3 MPa, the superheated steam blasted to thepreform may be condensed (dewed) on the surface thereof. When the steamis condensed, there is a fear of generating whitening or like on thesurface of a bottle at the time when the preform is blow-molded into thebottle.

Further, although the sterilization of the inner surface of the preformis essential, the sterilization of the outer surface may be performed byheating for the blow-molding treatment, that will be describedhereinafter, or may be performed by adding further desired sterilizationtreatment after the flow-molding treatment.

The superheated steam S is obtainable by using a commercially soldsuperheated steam generator 13. More specifically, a superheated steamgenerator (UPSS (Trade Name of TOKUDEN Kabushiki Kaisha) may be used.This generator, though not shown, has a structure in which an inductionheating coil is inserted into a central portion of a spiral ofwater-pass pipe composed of a spirally wound-up conductive member, wateris guided into the water-pass pipe, and an AC voltage is applied to theinduction heating coil. It may be possible to performfrequency-conversion of the AC voltage by an inverter so as to beenergized. By the application of the AC voltage, the induction heatingcoil generates alternate magnetic flux, and an induced current passesthe water-pass pipe, which is then heat-generated. The water passinginside the water-pass pipe is heated by this heat-generation and changedinto saturated steam, which then becomes superheated steam S which isthereafter taken out of the water-pass pipe.

It is further to be noted that the induction heating coil may be formedfrom a conductive tube, and by passing water through this conductivetube, heating effect may be further enhanced.

As the superheated steam S, it is possible to obtain steam havingpressure of more than 0.1 MPa and less than 0.3 MPa and temperature of200 to 500° C. By adopting the induction heating method mentioned above,it is possible to change the water into superheated steam of more than200° C. for a short time from the conduction starting time.

In FIG. 4, reference numeral 14 denotes a tubular nozzle. This tubularnozzle 14 is attached to a tip end of a conduit 15 connected to aterminal end of the water-pass pipe of the superheated steam generator13 so as to be suspended downward, and the tubular nozzle 14 has a tipend opening 14 a directed downward.

The preform 1 is conveyed along one direction directly under thecircular opening 14 a of the tubular nozzle 14 in a vertically electedstate with the mouth portion 1 a being directed upward. The conveyingmode may be a continuously conveying mode in which the preforms arecontinuously conveyed or may be an intermittently conveying mode inwhich each of the preforms 1 is temporarily stopped directly under theopening 14 a of the tubular nozzle 14. The preform 1 is capable of beingconveyed by clamping the support ring 3 thereof with a clamper, notshown.

In FIG. 4, reference numeral 16 denotes a nozzle in form of slit. Thisslit-shaped nozzle 16 is connected to a tip end of a branch tube 15 abranched from the conduit 15 in a manner such that the slit 16 a of thenozzle 16 faces a side surface of the preform 1. Preferably, a pair ofslit-shaped nozzles 16 are arranged so that the preform 1 is sandwichedfrom both side portions thereof, and the preform 1 is conveyed whilerotating an axis thereof. Although it is possible to convey the preformwithout being rotated, in such case, it may be required for pluralpaired slit-shaped nozzles to be arranged.

In the illustration of FIG. 4, although the slit-shaped nozzles areshown, annular-shaped nozzles such as tubular nozzles may be disposed tothe side surfaces or bottom surface in an opposing manner.

When the preform 1 is sterilized, the superheated steam S is alwayssupplied to the tubular nozzle 14 and the slit-shaped nozzle 16 from thesuperheated steam generator 13 so that the superheated steam S is jettedtoward the preform 1 from the circular opening 14 a of the tubularnozzle 14 and the slit 16 a of the slit-shaped nozzle 16. The nozzlediameters, angles, preform axis and the like are preliminarilyoptionally set so that the jetted superheated steam S contacts theentire inner surface of the preform 1.

According to the operation mentioned above, the superheated steam Sblasted from the opening 14 a of the tubular nozzle 14 enters inside thepreform 1 through the mouth portion 1 a thereof and contacts the entireinner surface thereof to thereby sterilize general bacteria, fungus,yeast and the like adhering to the inner surface of the preform 1.Further, since such sterilization can be achieved for a short time byblasting the superheated steam S into the interior of the preform 1, themouth portion 1 a of the preform can be prevented from being excessivelyheated from the interior side of the preform 1 and can be hence surelyprevented from being deformed.

Furthermore, the superheated steam S blasted from the slit 16 a of theslit-shaped nozzle 16 contacts the entire outer surface of the preform1, including the mouth portion 1 a, now rotating around the axisthereof, thus heating and sterilizing the outer surface of the preform1. Accordingly, general bacteria, fungus, yeast and the like adhering tothe outer surface of the preform 1 can be sterilized. Further, sincesuch sterilization can be achieved for a short time by blasting thesuperheated steam S into the interior of the preform 1, the mouthportion 1 a of the preform can be prevented from being excessivelyheated from the interior side of the preform 1 and can be hence surelyprevented from being deformed.

The preform sterilizing means using the superheated steam S isincorporated in an inline system shown in FIGS. 5 to 7 to therebyproduce a large amount of aseptic packaging products.

In this inline system, the preforms 1 are continuously delivered at apredetermined speed, and manufactured as aseptic packaging productsthrough processes shown in FIGS. 5 and 6.

First, as shown in FIG. 5(A), the preform 1 passes a position at whichthe tubular nozzle 14 and the slit-shaped nozzle 16 are disposed at apredetermined travelling speed while travelling with its verticallyelected posture being maintained. During this passing, as mentionedabove, the superheated steam S is blasted into the interior of thepreform 1 through the mouth portion 1 a and also blasted to the outersurface thereof, so that the entire surfaces including inner and outersurfaces of the preform 1 can be sterilized for a short time.

In the illustrated example, although the preform 1 is maintained in itsvertically elected posture, it may be possible for the preform 1 to haveits inverted posture.

Since such sterilization as described above is performed for a shorttime, the mouth portion 1 a of the preform 1 is free from deformationand resin material forming the preform is not excessively heated. Inaddition, since steam drain is not dewed and remains on the surface ofthe preform, the bottle 12 molded in the blow-molding process performedthereafter is never whitened.

Further, the inner and outer surfaces of the preform 1 may be sterilizedby alternatively shifting the tubular nozzle 14 and the slit-shapednozzle 16 in arrangement.

As shown in FIG. 5(B), a heater 17 is disposed in a wall-likearrangement along the conveying path of the preform 1, and the preform 1is heated, while travelling, by the heater 17 uniformly to a temperatureof about 90° C. to 130° C. suitable for the subsequent blow-moldingtreatment.

In the heating period, a spindle 18 is inserted into the preform 1through the mouth portion 1 a thereof to be suspended in the electedstate and rotated with the spindle 18 to be thereby uniformly heated bythe heater 17.

The preform 1 heated to a temperature suitable for the blow-moldingtreatment is subjected to the blow-molding treatment as shown in FIG.5(C), and then formed into the bottle 12 as a container.

A mold 19 as a blow-molding mold is continuously traveled at the samespeed as the travelling speed of the preform 1, the preform 1 isclamped, the blow-molding is performed to the preform within the mold19, and the mold 19 is thereafter opened.

The preform 1 has been heated substantially uniformly so that the entiretemperature of the preform increases to a temperature range suitable forthe molding treatment in the heating process shown in FIG. 5(B), andwith this temperature being maintained, the preform 1 is inserted intothe mold 19 together with the spindle 18 as shown in FIG. 5(C). Further,the blow nozzle 20 is inserted into the preform 1 passing the upperportion of the mold 19 and penetrating the spindle 18 in the mouthportion 1 a of the preform 1.

While travelling the mold 19, for example, primary air for blowing andsecondary air for blowing are blasted into the preform from the blownozzle 20, and the preform 1 is thereby swelled in the cavity C of themold 19 into the bottle 12 as final product.

As described above, when the bottle 12 is molded into the mold 19, themold 19 is opened while travelling, and as shown in FIG. 6(D), theproduct bottle 12 is taken out of the mold 19.

After the molding treatment, the bottle 12 is continuously traveled, andthereafter, as shown in FIG. 6(E), every kind of drinks a such asmineral water, tea, milk, carbonated drink, or like drink is filled asinner content into the bottle 12 through a filling nozzle 21, and asshown in FIG. 6(F), a cap 22 as a lid is applied to the bottle to sealthe bottle 12.

Further, it may be preferred that the sterilizing effect is enhanced bysterilizing the outer surface of the bottle 12 by the spray of asterilizing agent such as hydrogen peroxide or irradiation of electronray or like to the bottle 12 after the blow-molding treatment. In a casewhere the inner surface of the bottle is sterilized by the hydrogenperoxide water mist, it is necessary to passively reduce concentrationof the hydrogen peroxide to eliminate possibility of remaining of thehydrogen peroxide inside the bottle.

After the above treatments, the bottles 12 produced as product to bepackaged are collected and transported to markets.

An aseptic filling system for effecting the inline system mentionedabove has a configuration or structure such as shown in FIG. 7, forexample.

As shown in FIG. 7, this aseptic filling system is provided with apreform supplying machine 23 for subsequently supplying bottomed tubularpreforms 1 each having a mouth portion 1 a (see FIGS. 4, and 5(A)) at apredetermined interval, a blow-molding machine 24 and a filling machinefor filling the molded bottles 12 with the drink a and then sealing thebottles 12.

The preform supplying machine 23 is configured to take out the preforms1 one by one from a packaged large-sized container in which the preforms1 are accommodated, and the preforms 1 are transported to the firstconveying path described hereinafter. In the case where the conveyer 4mentioned above is arranged within the same factory in which the asepticfilling system is installed, it may be possible to directly connect theconveyer 4 to the preform supplying machine 23.

On a root from the preform supplying machine 23 to the filling machine25, there are provided a preform conveying means for conveying thepreforms 1 on the first conveying path, a mold conveying means forconveying the mold 19 (see FIG. 5(C)) having the cavity C of the shapecorresponding to the product of the bottle 12 on the second conveyingpath connected to the first conveying path, and a bottle conveying meansfor conveying the bottles 12 molded by the mold 19 on the thirdconveying path connected to the second conveying path.

The first conveying path of the preform conveying means, the secondconveying path of the mold conveying means and the third conveying pathof the bottle conveying means are communicated with each other, andgrippers and like members, not shown, for holding and conveying thepreforms 1 and the bottles 12 are provided on these conveying paths.

The preform conveying means is provided, on its first conveying path,with a preform conveyer 26 for subsequently conveying the preforms 1 ata predetermined interval. The preform conveying means is furtherprovided with a train of wheels 27, 28, 29 and 30 which receive thepreforms 1 from the terminal end of the conveyer 26 and a conveyer 31which receives the preforms 1 from the wheel 30 and then conveys thepreforms 1.

The tubular nozzle 14 and the slit-shaped nozzle 16 for blasting thesuperheated steam S to the preform 1 are provided on the slightlyupstream side of a portion of the preform supplying machine 23 at whichthe preform conveyer 26 is connected to the wheel 27. The superheatedsteam S is blasted toward the preforms 1 before heating (see FIGS. 4 and5(A)) from these nozzles 14 and 16, thereby uniformly heating andsterilizing the inner and outer surfaces of the preform 1.

These nozzles 14 and 16 may be provided on predetermined positions onthe outer periphery of the wheel, for example, before the preform 1reaches the conveyer 31.

The conveyer 31 includes an endless conveying chain extending longwisein the horizontal direction, and a heating unit 31 a is disposed alongthe endless conveying chain. A number of spindles 18, one shown in FIG.5(B), are mounted to the endless conveying chain at a constant pitchbetween adjacent ones. Each spindle 18 can rotate while travelling withthe running of the endless conveying chain. As shown in FIG. 5(B), thespindle 18 is inserted into the preform 1, through the mouth portion 1 athereof, conveyed to the conveyer 31 from the wheel 30, and the preform1 is held in its elected posture by the spindle 18.

The preform 1 is received by the conveyer 31 through the preformconveyer 26 and the train of the wheels 27, 28, 29, 30 and reciprocateswithin the heating unit 31 a by the conveyer 31. The heaters 17 areattached in a spread manner on the inner wall sections of the heatingunit 31 a (see FIG. 5(B)), and the preform 1 is heated by the heaterswhile being conveyed by the conveyer 31. The preform 1 rotates togetherwith the rotation of the spindle 18 during the travelling on theconveyer 31 and is uniformly heated by the heaters 17.

The blow-molding machine 24 is provided with plural sets of the molds 19and blow nozzles 20 (see FIG. 5(C)) receiving the preform 1 heated inthe heating unit 31 a of the preform supplying machine 23 and thenheating and molding the preform 1 into the bottle 12.

The second conveying path of the mold conveying means describedhereinbefore is arranged within the blow-molding machine. This secondconveying path includes a train of wheels 32, 33, 34, 29 and 35. It isfurther to be noted that the wheel 29 is commonly used in the train ofwheels 32, 33, 34, 29, 35 and the train of wheels 27, 28, 29, 30.

A plurality of such molds 19 and blow nozzles 20 are arranged around thewheel 33 and turned at a constant speed around the wheel 33 togetherwith the rotation of the wheel 33.

When the preform 1 heated in the heating unit 31 a of the preformsupplying machine 23 is received by the gripper, not shown, togetherwith the spindle 18, and is transferred to the mold 19 disposed aroundthe wheel 33, the mold 19 now split in opened state is closed to therebyholds the preform 1 as shown in FIG. 5(C). The preform 1 inside the mold19 are turned around the wheel 33 together with the mold 19 and the blownozzle 20. During such operation, the preform is subjected to theblow-molding treatment with highly pressurized air blown from the blownozzle 20, thereby being formed into a product bottle 12. As shown inFIG. 5(B), since the preform 1 is uniformly heated to the predeterminedtemperature by the heater 17, the blow-molding treatment can be smoothlyperformed.

When the preform 1 disposed inside the cavity C of the mold 19 tightlycontact the inner surface of the mold 19 and the bottle 12 is formed,the mold 19 is opened at a time when the mold 19 contacts the wheel 34,and the bottle 12 and the spindle 18 are then released. Then, the bottle12 is transferred to the gripper, not shown, of the wheel 34 from thespindle 18.

On the other hand, the spindle 18 after releasing the bottle 12 isreturned to the conveyer 31 through the wheel 32 and takes a positionready for holding and conveying another preform 1.

The bottle 12 released from the blow-molding machine 24 and reaches thewheel 34 is subjected to the inspection whether the bottle is right orwrong as a molded product (i.e., defective or not in molding treatment)by an inspection device 36 provided at the outer peripheral portion ofthe wheel 34.

The inspection device 36 is provided, not shown, with a bottle bodyinspection means for discriminating whether the bottle body is right orwrong, a support ring inspection means for discriminating whether thesupport ring 3 (FIG. 1) of the bottle 12 is right or wrong, a bottleneck ceiling inspection means for discriminating whether the neckceiling portion of the bottle 12 is right or wrong, and a bottle bottominspection means for discriminating whether the bottle bottom portion isright or wrong.

The bottle body inspection means, the support ring inspection means, andthe bottle neck ceiling inspection means are arranged along the outerperiphery of the wheel 34.

The bottle body inspection means, the support ring inspection means, andthe bottle neck ceiling inspection means are provided with lamps andcameras for photographing predetermined portions of the bottle 12, andimage processing units for processing the photographed images to therebydiscriminate the abnormality of the bottle with respect to the shape,injury, foreign material, color and the like thereof.

Further, the inspection device 36 is disposed optionally as occasiondemands, and the bottle body inspection means, the support ringinspection means and the bottle neck ceiling inspection means may beselectively arranged as occasion demands.

The bottle 12, which is judged as defective product after theinspection, is rejected from the conveying path by a rejecting device,not shown, and only acceptable product is conveyed to the wheel 35 fromthe wheel 34 through the wheel 29.

Further, it may be possible to additionally sterilize the outer surfaceof the bottle 12 after the blow-molding treatment by spray of steamincluding a sterilizing agent such as hydrogen peroxide or irradiationof electron ray, or possible to enhance the sterilizing effect for theinner surface of the bottle. For example, sterilization means such assterilizing agent including steam spray device or electron rayirradiation device may be provided for the wheel 29 or 35.

The filling machine 25 is provided therein with the third conveying pathof the bottle conveying means. This third conveying path includes atrain of wheels 37, 38, 39, 40, 41 and 42.

A filler 43 for filling the bottle 12 with the drink a and a capper 44for applying a cap 22 (see FIG. 6(F)) to the bottle 2 to seal the sameare disposed within the filling machine 25.

It is further to be noted that since known filler and capper are usableas such filler 43 and capper 22, the explanation thereof will be omittedherein.

The filling system is surrounded by a chamber member 45 (called merelychamber hereinafter), and the interior of the chamber 45 is sectionedinto an aseptic zone and gray zone. The preform supplying machine 23 andthe blow-molding machine 24 are disposed in the gray zone, and thefilling machine 25 is disposed in the aseptic zone, respectively.

Aseptic air sterilized in the HEPA is always blown into the gray zone,thereby conveying the bottle sterilized in the molding process to theaseptic zone without being secondarily contaminated by bacteria or like.

Further, in a case where a portion of the conveyer 4 that is downstreamside of the chamber 45 is connected to the preform supplying machine 23,the preform 1 sterilized by the hydrogen peroxide is further sterilizedby the superheated steam S and is then subjected to the blow-moldingtreatment to be thereby molded into a container such as bottle.Furthermore, in a case where the blow-molding machine 24 is connected tothe drink filling machine 25, the bottle 12 is filled up with the drinka, sealed and discharged as an aseptically filling packaged product.

Next, the function and operation of the preform sterilizing system shownin FIGS. 2 and 3 and the aseptic filling system shown in FIG. 7 will beexplained together with the preform sterilizing method.

Beforehand the sterilization treatment of the preform 1, the hydrogenperoxide water is preliminarily sprayed into the chamber 5 through thespray nozzle 10 and the interior of the chamber 5 is thus sterilized

Moreover, the interior of the chamber 37 of the aseptic filling system37 is likewise sterilized.

By driving the preform molding machine, the molded preform 1 is loadedon the upstream side of the conveyer 4 now travelling. The preform 1discharged from the preform molding machine is received on the upstreamside portion of the conveyer 4, and as shown in FIG. 2, the preforms 1are scraggly overturned on the conveyer 4.

The preform 1 on the conveyer 4 enters the chamber 5 together with theconveyer 4 and is sprayed with the hydrogen peroxide water by the spraynozzle 10.

The mist of the hydrogen peroxide water is discharged in a directioncrossing the conveyer 4 from both sides thereof, and the preform 1 isoverturned on the conveyer 4 by vibration or like, so that the hydrogenperoxide can uniformly adheres to the outer surface of the preform 1.

The hydrogen peroxide water mist flows into the preform 1 in theoverturned state through the mouth portion 1 a thereof to therebyuniformly adhere to the inner surface of the preform 1.

The hydrogen peroxide water mist discharged from the spray nozzle 10fills the interior of the chamber 5 and circulates therein, so that thehydrogen peroxide water mist adheres uniformly to the inner surface ofthe preform 1 while flowing therein. Thus, the entire surface of thepreform 1 can be uniformly sterilized by the hydrogen peroxide.

The preform 1 passes through the chamber 5 together with the conveyer 4while being blasted with the hydrogen peroxide water mist, and is thencharged into a container such as large luggage container.

This large container is transported to a factory in which the asepticfilling system is installed, and the container is opened there and thepreforms 1 in the large container are transferred to the preformsupplying machine 23.

Then, the preforms 1 are transferred to the conveyer 26 in an alignedstate by the preform supplying machine 23 and then transferred to theheating unit 31 a by means of the train of the wheels 27, 28, 29 and 30.

Before the preform 1 enters the heating unit 31 a, the superheated steamS is blasted toward the inner and outer surfaces of the preform 1 fromthe nozzles 14 and 16 shown in FIG. 4 (see FIG. 5(A)), therebysterilizing the entire surface of the preform 1.

In the heating unit 31 a, the preform 1 is entirely uniformly heated toa temperature of a range suitable for the following molding treatmentwhile being conveyed by the conveyer 31 (see FIG. 5(B)).

The preform 1 heated in the heating unit 31 a is held by the mold 19during the passing around the outer periphery of the wheel 33, and thepreform 1 trapped inside the mold 19 is swelled into a bottle as aproduct in the cavity C by blasting the highly pressurized air from theblow nozzle 20 (see FIG. 5(C)).

The molded bottle 12 (see FIG. 6(D)) is taken out of the mold 19 by thegripper of the wheel 34 after opening the same, and thereafter, isinspected by the inspection device 35 to confirm whether the moldingtreatment is preferably performed or not.

Thereafter, the bottles 12 travel inside the filling machine 25 whilebeing transferred to the train of the wheels 38, 39, 40, 41 and 42.

Within the filling machine 25, the bottle 12 is filled up with the drinka that has been subjected to the sterilizing treatment as shown in FIG.6(E) by the filler nozzle 21 of the filler 43. The sterilized cap 22 isthen applied to the mouth portion 1 a of the bottle 12 by the capper 44,and the bottle 12 is then sealed (see FIG. 6(F)) and discharged out ofthe chamber 45.

As described hereinbefore, since the filler 43 and the capper 44 areknown ones, the explanation of the drink filling method for the bottleand the bottle sealing method will be omitted herein.

Example 2

Mist of hydrogen peroxide water was produced by supplying hydrogenperoxide water of 35% concentration and pressurized air to a two-fluidspray, the thus produced mist was mixed with hot air having temperatureof 60° C., and then, the mist of the hydrogen peroxide water was sprayedinside a chamber through a nozzle. The chamber has a size of 600 mmwidth, and a conveyer has 1.5 m length. Preforms, each being formed intoa bottle of 500 mm, were supplied to the conveyer by the number of 860bottles/min., and the conveyer was driven at a speed of 0.2/sec. At thistime, the hydrogen peroxide water of amount of about 50 mg adhered toeach preform. Furthermore, preforms, each being formed into a bottle of2000 mm, were supplied by the number of 250 bottles/min., and the sameoperation was performed. At this time, the hydrogen peroxide water ofamount of about 150 mg adhered to each preform. Such preforms weresubjected to the following treatment.

Superheated steam of flow amount of 0.7 g/sec. generated by heatingwater by a superheated steam generator of induction heating system wassprayed to each inner surface of the preform from a nozzle having innerdiameter of 8 mmϕ at blasting temperature of 300° C. for 5 sec.

In such spraying, the sterilizing effect is shown in Table 1 in anevaluation with indicating bacillus inoculated on the inner surface ofthe initial preform, and it was confirmed that this sterilizing effectis applicable to every drink.

TABLE 1 B. sub. A. nig For 500 mL 3.1D More than 6.0D For 2 L 3.0D Morethan 6.0D

In the above Table 1, term “B. sub.” is an abbreviated term of “BaciLLussubtiLis”, and “A. nig.” is an abbreviated term of “AspergiLLus niger”.“D” is a D-valve indicating the sterilizing effect.

Further, an experiment result of deformed amount of the inner diameterof the mouth portion of the preform indicated no problem for maintainingthe sealing performance of a cap as shown in the following Table 2.

TABLE 2 Before Blasting Of After Blasting Of Superheated SteamSuperheated Steam For 500 mL 21.77 mm 21.75 mm For 2 L 21.75 mm 21.71 mm

Example 3

The hydrogen peroxide water adhered to each preform having inner volumeof 500 ml for bottle as in the first example 1. Furthermore, superheatedsteam of flow amount of 0.7 g/sec. generated by heating water by asuperheated steam generator of an induction heating system was sprayedto the inner surface of each preform from a nozzle having inner diameterof 8 mmϕ at blasting temperature in a range of 180 to 550° C. for 10 to3 sec.

The sterilizing effect and the deformation of the inner diameter of thepreform by such superheated steam spraying is shown in the followingTable 3.

TABLE 3 Blasting Blasting Sterilizing Temperature (° C.) Time (sec.)Effect Deformation 180 10 X X 250 6 ◯ ◯ 350 4 ◯ ◯ 450 3 ◯ ◯ 550 3 ◯ X

Further, it is to be noted that, in the above Table 3, the sterilizationeffect is shown with [∘] (good) in the case where the D-value withrespect to BaciLLus subtilis is not less than 6, and the other cases areshown with [x] (not good). With respect to the deformation of the innerdiameter, in the case where the inner diameter of the preform isdeformed by less than 0.05 mm is shown [∘] (good), and the other casesare shown with [x] (not good).

Embodiment 3

Hereunder, the third embodiment 3 of the present invention will beexplained.

Preforms as targets in the present embodiment are the same as those inthe first embodiment 1.

A device for sterilizing the preform 1 has a structure or configurationshown in FIGS. 8 and 9.

In FIGS. 8 and 9, reference numeral 4 denotes an endless belt-typeconveyer. A preform molding machine, not shown, is disposed on theupstream side in the travelling direction of the conveyer as indicatedwith an arrow. The preform 1 after being molded and released from thepreform molding machine is received by using a hopper or like, notshown, on the upstream side of the conveyer 4. As shown in FIG. 8, themolded preforms 1 are laid in the scraggly overturned manner on theconveyer 4.

An intermediate portion of the conveyer 4 can be traveled in thehorizontal direction, and in this intermediate portion, the first andsecond chambers 5 a and 6 a are arranged in an aligned manner and areapplied to the conveyer 4 each in form of hood.

As shown in FIGS. 8 and 9, the first chamber 5 a is defined by both sidewall sections 47 disposed so as to sandwich the conveyer 4 from bothsides, front and rear wall sections 48 and 49 disposed at front and rearends of both the side wall sections 47, and a top wall section 50shielding the upper side of both the side wall sections 47 and the frontand rear wall sections 48 and 49.

A preheating nozzle (nozzle for preheating) 51 exhausting hot air H in adirection crossing the conveyer 4 from the side edge side of theconveyer is mounted to each of both the side wall sections 47. Althoughit may be possible to mount one preheating nozzle 51 to each side wallsection 47, it is preferred to arrange a plurality of preheating nozzles51 to each side wall section along the travelling direction of theconveyer 4.

Further, the preheating nozzle 51 having a circular opening or aslit-shaped opening may be preferably used.

The aseptic hot air H is supplied from the upstream side of eachpreheating nozzle 51, and the hot air H is discharged into the firstchamber 5 a through the tip ends of the respective preheating nozzles 51and blasted to the surface of the preform 1 on the conveyer 4 to therebypreheat the surface of the preform 1 by the heat of the hot air H.

It is preferred that the temperature of the hot air H discharged fromthe preheating nozzle 51 is 80 to 130° C., and the surface temperatureof the preform 1 preheated by the hot air H is preferably of 40 to 70°C. In a case of less than 40° C., the temperature of the superheatedsteam S or like basted in the subsequent stage is not so lowered, and ina case of more than 70° C., the mouth portion 1 a of the preform 1 maybe deformed.

Within the first chamber 5 a, the hot air H is discharged in a directioncrossing the conveyer from both sides of the conveyer 4, and since thepreform 1 can be horizontally overturned on the conveyer 4 by vibrationor like, the hot air can uniformly contact the surface of the preform 1.At the same time, since the hot air flows inside the preform 1 throughthe mouth portion 1 a of the overturned preform 1, thereby alsouniformly contacting the inner surface of the preform 1. Furthermore,the hot air H discharged from the preheating nozzle 51 fills theinterior of the chamber 5 a and circulates therein, so that this flow ofthe hot air H uniformly adheres to the surface of the preform 1. Thus,the entire surface of the preform 1 can be suitably preheated by the hotair H.

The front and rear wall sections 48 and 49 of the first chamber 5 a areformed with openings 48 a and 49 a through which the conveyer 4 and thepreform 1 placed thereon can pass. In addition, an exhaust duct 52 isconnected to the top wall section 50 of the first chamber 5 a. The hotair H discharged into the first chamber 5 a is sucked into the exhaustduct 52 by driving a blower, not shown, and then discharged outside thefirst chamber 5 a.

A hot air (H) generation section is provided, as shown in FIG. 10(A),with a blower 53, a sterilizing filter 54 and an electric heater 55.Outdoor air taken by the blower 53 is sterilized by the sterilizingfilter 54, then heated by the electric heater 55 to a predeterminedtemperature, and thereafter, is fed to the respective preheating nozzles51 through pipes or like as aseptic hot air H.

Further, it may be possible to add heated steam to air flowing towardthe sterilizing filter 54 from the blower 53. According to such additionof the heated steam, the air is preheated and humidified, therebyenhancing heat capacity of the aseptic hot air H from the electricheater 55. Moreover, the sterilizing filter 54 may be constituted with aprefilter and an ULPA filter which are connected in series. Theprovision of the prefilter elongates duration of life of the ULPAfilter.

As shown in FIGS. 8 and 9, a second chamber 6 a is disposed adjacent tothe first chamber 5 a on the downstream side of the conveyer 4.

The second chamber 6 a is also defined, as like as the first chamber 5a, by both side wall sections 56 disposed so as to sandwich the conveyer4 from both sides, front and rear wall sections 57 and 58 disposed atfront and rear ends of the both side wall sections 56 and 49, and a topwall section 50 shielding the upper side of both the side wall sections56 and the front and rear wall sections 48 and 49.

A sterilization nozzle (nozzle for sterilization) 60 exhaustingsuperheated steam S in a direction crossing the conveyer 4 from the sideedge side of the conveyer 4 is mounted to each of both the side wallsections 56. Although it may be possible to mount one sterilizationnozzle 60 to each side wall section 56, it is preferred to arrange aplurality of sterilization nozzles 60 51 to each side wall section 56along the travelling direction of the conveyer 4.

Further, the sterilization nozzle 60 having circular opening orslit-shaped opening may be preferably used.

The superheated steam S is supplied from the upstream side of eachsterilization nozzle 60, and the superheated steam S is discharged intothe second chamber 6 a through the tip ends of the respectivesterilization nozzles 60.

The superheated steam S is a mixed gas of water and hydrogen peroxidemade from water mixed with hydrogen peroxide. When this superheatedsteam S is blasted to the surface of the preform 1 on the conveyer 4,the surface of the preheated preform 1 is sterilized by the combinedeffects due to the heat of the superheated steam S and the sterilizingfunction of the hydrogen peroxide.

A temperature for blasting the superheated steam S to the preform 1 ispreferably of 150 to 500° C., and more preferably, 250 to 400° C. Withinthe temperature range of 150 to 500° C., only the surface of the preformis exposed to high temperature, and thereby, fungus or like adhering tothe surface of the preform 1 can be sterilized for a short time. In thecase of the temperature of less than 150° C., long time blasting of thesuperheated steam S is required for the sterilization, which will resultin temperature increasing of the PET itself constituting the preform 1,hence leading to deformation of the preform. In the case of more than500° C., the temperature of the PET will be increased for a short time,which will lead to easy deformation of the preform 1.

A pressure of the superheated steam S to be blasted to the preform 1 ishigher than atmospheric pressure, and is preferably more than 0.1 MPaand less than 0.3 MPa. In a case where this pressure is near 0.1 MPa,even if the superheated steam S contacts the preform and the temperaturethereof is lowered, there is less possibility of condensation(bedewing), and in a case where this pressure is more than 0.3 MPa, whenthe superheated steam S is blasted to the preform 1, the condensationthereof may be formed on the surface of the preform 1. When suchcondensation is formed, there may cause a fear of generating whiteningto the surface of the bottle 2 at the time of blow-molding the preforminto a bottle or like.

Furthermore, it is preferred that the time for blasting the superheatedsteam S to the preform 1 is within 1.0 to 10.0 sec. In the case of lessthan 1.0 sec., defective sterilization may be likely caused, and in thecase of more than 10.0 sec., the mouth portion 1 a of the preform 1 maybe likely deformed. This superheated steam blasting time can increasethe sterilizing effect by the superheated steam S consisting of watermixed with the hydrogen peroxide because the surface of the preform 1 ispreliminarily heated as mentioned hereinbefore in comparison with a casein which the preheating is not effected.

It is preferred that the hydrogen peroxide to be mixed with the waterhas concentration of 0.5 to 15%. In the case of less than 0.5%, thesterilizing power against the spore-forming bacteria is insufficient,and in the case of more than 15%, the hydrogen peroxide will remainmuch.

The superheated steam S is discharged in a direction crossing theconveyer 4 from both sides of the conveyer 4 within the second chamber 6a, and since the preform 1 is overturned on the conveyer 4 by vibrationor like, the superheated steam S is uniformly contacts or adheres to thesurface of the preform 1. Moreover, since the superheated steam Sdischarged from the sterilization nozzle 20 fills and circulates in thesecond chamber 6 a, this superheated steam S also uniformly contacts oradheres to the surface of the preform 1. Thus, the entire surface of thepreform 1 is properly sterilized by the superheated steam S and thehydrogen peroxide contained therein.

The front and rear wall sections 57 and 58 of the second chamber 6 a areformed with the openings 57 a and 58 a so that the conveyer 4 and thepreforms 1 placed thereon can pass through the openings. An exhaust duct61 is connected to the top wall section 59 of the second chamber 6 a.The superheated steam S discharged into the second chamber 6 a is suckedinto the exhaust duct 61 by the operation of the blower, not shown, andthen discharged outside the second chamber 6 a.

The superheated steam S can be obtained by using a commercially soldsuperheated steam generator 62 shown in FIG. 10(B). More specifically,the superheated steam generator of UPSS (Trade Name of TOKUDEN KabushikiKaisha). This generator is composed of such a structure as that aninduction heating coil is inserted into a central portion of spiral of awater-pass pipe formed from spirally wound-up conductive body, notshown, in which water mixed with the hydrogen peroxide is guided intothe water-pass pipe and A.C. voltage is applied to the induction heatingcoil to thereby generate superheated steam. Current conduction may bepossible by frequency-converting the A.C. voltage by an inverter. By theapplication of the A.C. voltage, the induction heating coil generate theA.C. flux, an induction current passes in the water-pass pipe, and thewater-pass pipe is thereby heated. According to this heat generation ofthe water-pass pipe, the water flowing the water-pass pipe and thehydrogen peroxide are heated and changes to a saturated steam, which isthen converted into the superheated steam S, which is then taken out ofthe water-pass pipe.

Further, by forming the induction heating coil as a conductive tube, theheating effect to the water passing through this water-pass pipe may beenhanced.

According to the superheated steam generator 62 of the structurementioned above, it is possible to obtain a superheated steam as thesuperheated steam S having a pressure of 0.1 MPa and a temperature of150 to 500° C. By adopting the induction heating method mentioned above,the water mixed with the hydrogen peroxide is changed into thesuperheated steam S having the temperature of 150 to 500° C. for a shorttime from the conduction-start time. More specifically, the superheatedsteam S is a high-temperature mixed gas of the water and the hydrogenperoxide, and this superheated steam S is taken out from the tip end ofthe conduit 63 connected to the terminal end of the water-pass pipe ofthe superheated steam generator 22 and then distributed to therespective sterilization nozzles 60.

The downstream side further than the second chamber 6 a of the conveyer4 extends toward a large container, not shown. The preform 1 sterilizedwithin the second chamber 6 a by the superheated steam S is deliveredtoward and then into the large container by the conveyer 4. This largecontainer is sealed after the accommodation of predetermined amount ofthe preforms and stored, and then transferred to a factory in which thepreforms are molded into bottles.

Further, in an arrangement in which the downstream side further than thesecond chamber 6 a of the conveyer 4 is connected to the blow-moldingmachine, the sterilized preform 1 is immediately blow-molded into acontainer such as bottle. Moreover, in an arrangement in which theblow-molding machine is connected to the content filling machine, thecontainer such as bottle is filled with a content such as drink, sealedand then discharged as the aseptic package of products.

Hereunder, function of the preform sterilization apparatus of thestructure mentioned above will be described together with a preformsterilizing method.

Beforehand the starting of the sterilizing treatment of the preform 1,the interiors of the first and second chambers 5 a and 6 a arepreliminarily sterilized by spraying chemical agent such as hydrogenperoxide water or like.

The molded preforms 1 are loaded on the upstream side portion of thetravelling conveyer 4 by driving the preform molding machine. Thepreforms 1 discharged from the preform molding machine is received atthe upstream side portion of the conveyer 4 in the overturned manner onthe conveyer 4 as shown in FIGS. 8 and 9.

The preform 1 on the conveyer 4 is moved into the first chamber 5 a withthe conveyer 4, and is then preheated therein by blasting the hot air Hdischarged from the preheating nozzle 51.

The hot air H is discharged within the first chamber 5 a in a directioncrossing the conveyer 4 from both sides thereof, and the preform 1 isoverturned on the conveyer 4 by vibration or like, so that the hot air Hcan uniformly contact the outer surface of the preform 1.

The hot air H flows into the preform 1 in the horizontally overturnedstate through the mouth portion 1 a thereof to thereby uniformly adhereto the inner surface of the preform 1.

The hot air H discharged from the preheating nozzle 51 fills theinterior of the chamber 5 a and circulates therein, so that the hot airH adheres uniformly to the inner surface of the preform 1 while flowingtherein. Thus, the entire surface of the preform 1 can be uniformlysterilized by the hot air H.

The preform 1 passes through the chamber 5 together with the conveyer 4while being blasted with the hot air H, and then enters the secondchamber 6 a in which the preform 1 is sterilized by blasting thesuperheated steam S discharged from the sterilization nozzle 60.

The superheated steam S is blasted to the preform 1 as a hightemperature mixture gas of the water and the hydrogen peroxide.

The superheated steam S is discharged within the second chamber 6 a in adirection crossing the conveyer 4 from both sides thereof, and thepreform 1 is overturned on the conveyer 4 by vibration or like, so thatthe superheated steam S can uniformly contact or adhere to the outersurface of the preform 1.

The superheated steam S flows into the preform 1 in the horizontallyoverturned state through the mouth portion 1 a thereof to therebyuniformly contact or adhere to the inner surface of the preform 1, thusthe preform 1 being sterilized.

The superheated steam S discharged from the sterilization nozzle 60fills the interior of the chamber 6 a and circulates therein, so thatthe superheated steam S uniformly contacts or adheres to the innersurface of the preform 1 while flowing therein.

According to the above sterilizing treatment, general bacteria, fungus,yeast and the like adhering to the surfaces of the preform 1 can besterilized by the heat of the superheated steam S and the hydrogenperoxide, and the spore-forming bacteria adhering to the surface of thepreform 1 can be also sterilized by the hydrogen peroxide.

The preforms 1 subjected to the sterilizing treatment discharged fromthe second chamber 6 a together with the travelling of the conveyer 4are then transferred into the large container, or transferred to theblow-molding machine and filling machine without being packaged in thecontainer and then discharged as aseptic packaged products.

It is further to be noted that the present invention is not limited tothe above-described embodiment and many other modification may beembodied.

Example 4

The first chamber 5 a and the second chamber 6 a have size of 1000 mmwidth, and 1500 mm length, and 200 mm height, respectively. Preforms,each being formed into a bottle of 500 ml, were supplied to the conveyerby the number of 860 bottles/min., and the conveyer was driven at apredetermined speed. In this operation, the temperature of the hot air Hin the first chamber 5 a, and the blasting temperature of thesuperheated steam S in the second chamber 6 a, and the concentration ofthe hydrogen peroxide were set as shown in the Table 4, which also showsobtained sterilization results.

TABLE 4 Superheated Hot Air Steam Temper- Blasting Hydrogen atureTemperature Peroxide In First In Second Travelling Concen- ChamberChamber Speed tration (%) (° C.) (° C.) (m/sec.) B. sub. A. niger 3 100200 0.2 5.3D More Than 6.0D 3 100 400 0.2 6.0D More Than 6.0D 3 NO 4000.2 4.0D 6.0D 3 100 500 0.2 More More Than 6.0D Than 6.0D 10 100 400 0.5More More Than 6.0D Than 6.0D 10 NO 400 0.5 5.5D More Than 6.0D 10 80400 0.2 6.0D More Than 6.0D

In the above Table 4, term “B. sub.” is an abbreviated term of “BaciLLussubtilis”, and “A. nig.” is an abbreviated term of “AspergiLLus niger”.“D” is a D-valve indicating the sterilization effect.

As is apparent from the above Table 4, in the case where the superheatedsteam S added with the hydrogen peroxide was blasted with respect to theA. niger, the sterilizing effect more than 6.0 D could be obtainedregardless of the preheating to the surface of the preform by the hotair. With respect to the B. sub, in the case where the preheating wasperformed and the superheated steam added with the hydrogen peroxide wasblasted, the sterilizing effect more than 6.0 D could be obtained, incomparison with the case of no preheat treatment, without increasing thesuperheated steam temperature or increasing the blasting amount thereof.

Embodiment 4

Hereunder, an embodiment 4 of the present invention will be described,and a preform as a target to be sterilized by the present invention isthe same as that in the embodiment 1.

An apparatus for sterilizing the preform 1 has the same structure asthat of the embodiment 3 shown in FIGS. 8 and 9.

In this embodiment 4, different from the embodiment 3, the superheatedsteam S not including hydrogen peroxide is supplied from the upstreamside of the respective sterilization nozzles 60, and this superheatedsteam S is discharged into the second chamber 6 a from the tip ends ofthe respective sterilization nozzles 60 and then blasted to the surfacesof the preforms on the conveyer 4. The surfaces of the preforms 1 thatare preheated in the first chamber 5 a are thus sterilized by the heatof the superheated steam S.

The temperature of the superheated steam S to be blasted to the preform1 is preferably of 200 to 700° C., and more preferably, 250 to 500° C.In the case of the temperature range within 200 to 700° C., only thesurface of the preform is exposed to highly heated temperature tothereby spore-forming bacteria adhering to the surface of the preformcan be sterilized for a short time. In the case of less than 200° C., itis required for the preform to be blasted with the superheated steam fora long time for the sterilization, which leads to highly increasedtemperature of a PET forming the preform and the preform is hence liableto be deformed. On the other hand, in the case of more than 700° C., thePET forming the preform is itself highly heated for a short time, and ishence liable to be easily deformed.

The pressure of the superheated steam to be blasted to the preform isone higher than atmospheric pressure and is preferably of higher than0.1 MPa and less than 0.3 MPa. In the case of near 0.1 MPa, even if thetemperature is lowered in contact of the superheated steam S to thepreform, there is less possibility of condensation of the steam, but inthe case of more than 0.3 MPa, the superheated steam S blasted to thepreform may be condensed on the surface thereof. When the steam iscondensed, there is a fear of generating whitening or like on thesurface of a bottle at the time when the preform is blow-molded into thebottle.

Furthermore, it is preferred that the time for blasting the superheatedsteam S to the preform 1 is within 1.0 to 10.0 sec. In the case of lessthan 1.0 sec., defective sterilization may be likely caused, and in thecase of more than 10.0 sec., the mouth portion 1 a of the preform 1 maybe likely deformed. This superheated steam blasting time can increasethe sterilizing effect by the superheated steam S because the surface ofthe preform 1 is preliminarily heated as mentioned hereinbefore incomparison with the case in which the preheating is not effected, and asa result, the superheated steam blasting time can be reduced and lessenergy consumption can be performed.

The superheated steam S is discharged in a direction crossing theconveyer 4 from both sides of the conveyer 4 within the second chamber 6a, and since the preform 1 is overturned on the conveyer 4 by vibrationor like, the superheated steam S uniformly contacts the surface of thepreform 1. At the same time, the superheated steam S flows inside theoverturned preform through the mouth portion 1 a thereof, and thus,superheated steam S uniformly contacts the inner surface of the preform1. Moreover, since the superheated steam S discharged from thesterilization nozzle 60 fills and circulates in the second chamber 6 a,this superheated steam S also uniformly adheres to the surface of thepreform 1. Thus, the entire surface of the preform 1 is suitablysterilized by the superheated steam S.

The superheated steam S discharged into the second chamber 6 a is suckedinto the exhaust duct 61 by the operation of the blower, not shown, andthen discharged out of the second chamber 6 a.

The superheated steam S can be obtained by using a commercially soldsuperheated steam generator 62 shown in FIG. 10(B). By guiding waterinto a water-pass pipe and by applying the A.C. voltage to the inductionheating coil, the water-pass pipe is heated. The heat generation of thewater-pass pipe causes the water to be saturated steam state, which isthen converted into the superheated steam S, which is thereafter takenout of the water-pass pipe.

According to the superheated steam generator 62 of the structurementioned above, it is possible to obtain a superheated steam as thesuperheated steam S having a pressure of 0.1 MPa and a temperature of200 to 700° C. By adopting the induction heating method mentioned above,the water can be converted into the superheated steam S having thetemperature of more than 200° C. for a short time from theconduction-start time. This superheated steam S is taken out from thetip end of the conduit 63 connected to the terminal end of thewater-pass pipe of the superheated steam generator 62 and thendistributed to the respective sterilization nozzles 60.

The downstream side further than the second chamber 6 a of the conveyer4 extends toward a large container, not shown. The preform 1 sterilizedwithin the second chamber 6 a by the superheated steam S is transferredtoward and then into the large container by the conveyer 4. This largecontainer is sealed and stored after the accommodation of predeterminednumbers of the preforms, and then transferred to a factory in which thepreforms are molded into bottles.

Further, in an arrangement in which the downstream side further than thesecond chamber 6 a of the conveyer 4 is connected to the blow-moldingmachine, the sterilized preform 1 is immediately blow-molded into acontainer such as bottle. Moreover, in an arrangement in which theblow-molding machine is connected to the content filling machine, thecontainer such as bottle is filled with a content such as drink, sealedand then discharged as the aseptic package of products.

Example 5

The first chamber 5 a and the second chamber 6 a have a size of 1000 mmwidth, and 1500 mm length, and 200 mm height, respectively. Preforms,each being formed into a bottle of 500 ml, were supplied to the conveyerby the number of 860 bottles/min., and the conveyer was driven at apredetermined speed. In this operation, the temperature of the hot air Hin the first chamber 5 a, and the blasting temperature of thesuperheated steam S in the second chamber 6 a, and the concentration ofthe hydrogen peroxide were set as shown in the Table 5, which also showsobtained sterilization results.

TABLE 5 Superheated Steam Hot Air Blasting Temperature Temperature InFirst In Second Travelling Chamber Chamber Speed (° C.) (° C.) (m/sec.)B. sub. A. niger 100 300 0.2 2.2D 5.0D 100 500 0.2 2.8D 6.0D 100 500 0.52.0D 5.0D 130 500 0.2 3.0D More Than 6.0D 100 700 0.2 3.1D More Than6.0D NO 500 0.2 1.0D 3.0D  50 500 0.2 1.8D 3.5D

In the above Table 5, term “B. sub.” is an abbreviated term of “BaciLLussubtiLis”, and “A. nig.” is an abbreviated term of “AspergiLLus niger”.“D” is a D-valve indicating the sterilizing effect.

As is apparent from the above Table 5, in the case where the preform wasnot preheated, the sterilizing effect was 3.0 D with respect to the A.niger, but in the case where the preform was preheated by blasting thehot air, the sterilizing effect more than 6.0 D with respect to the A.niger could be obtained without increasing the superheated steamtemperature or increasing the blasting amount thereof.

REFERENCE NUMERAL

-   -   1—preform    -   1 a—mouth portion of preform    -   4—conveyer    -   5—chamber    -   5 a—first chamber    -   6 a—second chamber    -   10—spray nozzle    -   51—preheating nozzle    -   60—sterilization nozzle    -   H—hot air    -   M—hydrogen peroxide water mist    -   S—superheated steam

1. An apparatus for sterilizing a preform comprising: a conveyer onwhich a preform, having a bottomed tubular shape, is laid in anirregular lying state; a chamber provided to a horizontally travelingportion of the conveyer; and a spray nozzle that sprays hydrogenperoxide water from both sides of the conveyer in a direction crossingthe conveyer in the chamber so as to adhere the hydrogen peroxide waterto inner and outer surfaces of the preform on the conveyer.